The patent application PCT WO 2007/148301 describes a device for producing an airplane fuselage in which a lamination mandrel is delimited by an external surface which defines a rotation solid (in particular a cylinder) with respect to a symmetry axis. The lamination mandrel is adapted to receive and support a band of impregnated synthetic material which is wound and deposited on the external surface of the mandrel in a lamination step forming a plurality of overlapped layers. Said overlapped layers are subjected to a subsequent polymerisation process under vacuum in an autoclave for forming a structural section of the airplane (typically a tubular portion of fuselage).
The lamination mandrel comprises a plurality of sectors angularly spaced about the axis and mobile between: an expanded lamination position in which the sectors have greater rectilinear edges parallel to the axis arranged side by side and the external surfaces of the sectors opposite the axis define the external surface; and a contracted disassembling position in which the sectors approach the axis moving away from the trace of the surface to reduce the axial dimensions of the mandrel allowing extraction of the lamination mandrel from the structural section of the airplane at the end of the polymerisation process under vacuum.
In the expanded lamination position it is essential for the sectors to maintain an angularly stable position with respect to one another since any slight movements between the parts can irreparably alter the geometry of the structural section.
For example the patent applicant has pointed out that a lamination mandrel used for producing structural sections of large passenger airplanes must have low dimensional tolerances, below—for example—0.5 mm.
The need is therefore felt to produce a constraint system of sectors which allows the indexing of two sectors preventing any relative movement between the sectors during the above-mentioned lamination step (in said step the mandrel can be rotated) and during the subsequent movement and maintenance of the lamination mandrel in the autoclave.